The present invention relates to optical scanners and more specifically to an apparatus for sensing different attenuation windows within an optical scanner.
Optical scanners are well known for their usefulness in retail checkout and inventory control. Optical scanners generally employ a single laser source, the light from which is collimated and focused to produce a scanning beam. They may additionally employ a mirrored spinner to direct the beam against a plurality of stationary mirrors, and a detector to collect the beam after it is reflected by a bar code label. The pattern produced by such a scanner is characterized by lines oriented at various angles to one another.
It has been difficult for scanner manufacturers to achieve an economic advantage by using the same scanner components in a variety of product offerings. One of the problems that has made such achievement difficult has been compliance with laser safety standards. A countertop scanner which employs a scratch-resistant glass requires a more powerful laser beam than a scanner without such a glass because the glass attenuates the beam as it passes through.
Therefore, it would be desirable to provide an apparatus for an optical scanner which can allow a single scanner design to be used in a variety of product offerings by sensing different attenuation levels of scanning beams and adjusting laser power to optimize performance while complying with laser safety standards. It would also be desirable for the apparatus to be capable of adjusting detection threshold levels and speaker volumes.